Preparation of BiVO4/ZnO composite film with enhanced visible-light photoelectrocatalytic activity

In this work, a BiVO4/ZnO composite film was fabricated via a combination of the liquid phase deposition technique and the successive ionic layer adsorption and reaction (SILAR) process. Scanning electron microscopy and X-ray diffraction observations revealed that wurtzite ZnO and monoclinic BiVO4 were successfully formed in the composite film. UV visible spectra indicated that the formation of the BiVO4/ZnO film resulted in improved absorption and an obvious redshift. Photoluminescence analysis revealed that the BiVO4/ZnO film exhibited superior charge-transfer properties to pure ZnO and BiVO4 films. The fabricated BiVO4/ZnO film was applied to the photoelectrocatalytic (PEC) degradation of tetracycline. The BiVO4/ZnO film showed higher visible-light PEC activity than did pure ZnO and BiVO4 films. Moreover, the tetracycline degradation efficiency achieved by the PEC process over the BiVO4/ZnO film was higher than those achieved using the photolysis, electrochemical oxidation, and photocatalysis processes. The BiVO4/ZnO film was able to effectively remove more than 90% tetracycline when the initial concentration of tetracycline was lower than 10 mg/L.